Calender stacks having transverse pressure sensing and adjustment means



y 7 w. c. NOTBOHM ETAL 3,331,313

CALENDER STACKS HAVING TRANSVERSE PRESSURE SENSING AND ADJUSTMENT MEANS Filed Sept. 24, 1965 FIG-3 72 25 70 WILLARD c. NO WALTER E. ROJECKIHG ATTORNEYS United States Patent 3,331,313 CALENDER STACKS HAVING TRANSVERSE PRES- SURE SENSING AND ADJUSTMENT MEANS Willard C. Notbohm, Walter E. Rojecki, and Paul M.

Schafirath, all of Watertown, N.Y., assignors to The Black Clawson Company, Hamilton, Ohio, a corporation of Ohio Filed Sept. 24, 1965, Ser. No. 490,014 Claims. (Cl. 100-47) This invention relates. to paper machinery, and more particularly to paper machine calender stacks.

The invention is especially concerned with overcoming various defects arising in the operation of calender stacks of conventional construction, such for example as barring of the rolls and excessive wear of rolls to abnormal crowns, all of which contribute to non-uniform calendering of the paper web as well as to excessive maintenance requirements. In accordance with the invention, it has been determined that these defects and their related problems result from non-uniform nip conditions caused by unstable conditions of the rolls with respect to lateral forces, which in turn derive from conventional calender stack construction wherein all the rolls are held with their axes in a common plane. More specifically, it has been determined that these defects result from the fact that the pressures on the intermediate rolls and the torque effects on each intermediate roll caused by driving and driven engagement with its adjacent rolls all tend to urge the intermediate roll generally transversely of the plane defined by its adjacent rolls.

It is a'prirnary object of the present invention to provide a calender stack capable of operation with a minimum of problems of barring and excessive wear of the rolls, which is characterized by the fact that one or more of the intermediate rolls is provided with an adjustable mounting such that the axis thereof can be offset relative to the plane defined by the axes of the two immediately adjacent rolls to a position wherein the resultant of the pressure and torque forces thereon laterally of the plane of the stack is reduced to a minimum.

Another object of the invention is to provide such a calender stack which is so constructed that the lateral position of each adjustably' mounted intermediate roll can be re-adjusted in accordance with changed operating conditions of pressure, speed, and/or the caliper of the paper web until the resulting thrust forces are reduced to a minimum.

An additional object of the invention is to provide a calender stack as outlined above which is constructed for automatic operation of the adjusting mechanism for each adjustably mounted intermediate roll in response to the action of a strain gauge or other continuously or intermittently effective force-measuring device capable of sensing the thrust forces on the associated intermediate roll in directions generally transverse of the plane defined by the axes of the two immediately adjacent rolls.

Additional objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings- FIG. 1 is a fragmentary view in side elevation show ing one side of an open side calender stack constructed in accordance with the invention;

FIG. 2 is a fragmentary view in perspective, partly broken away, showing the adjusting mechanism for one end of one of the adjustable intermediate rolls in the calender stack of FIG. 1;

FIG. 3 is a fragmentary view similar to FIG. 1 showing another form of the invention;

FIG. 4 is a fragmentary section on the line 4-4 of FIG. 3; and

, causing corespondingly progressively worse with increase in the 3,331,313 Patented July 18, 1967 FIG. 5 is a fragmentary diagrammatic view showing the application of the invention to a calender stack of the closed side type.

Referring to the drawings, which illustrate preferred embodiments of the invention, FIGS. 1 and 2 illustrate one application of the invention to one side of an open side calender stack, it being understood that the same construction is duplicated at the opposite side of the stack. The frame in FIG. 1 includes a base 10, column 11 and top piece 13 which is connected in the usual way (not shown) to the corresponding top piece of the opposite frame. The king roll 15 is mounted on base 10 by fixed bearings 16, and it is driven as indicated diagrammatically at 17.

Each of the queen roll 20, top roll 21 and intermediate rolls 22 is individually supported from the column 11 for generally vertical movement by an arm 25 having a pivotal connection 26 at one end of the column 11 and having the bearing 27 for the associated roll mounted on its other end. The lifting screw 30 depends from a motor 31 on the top piece 13, and a nut 33 forms an adjustable connection between the screw 30 and the under side of each arm 25. A fluid pressure cylinder 35 is also mounted on the top piece 13 and connected through a depending rod 36 with the bearing 27 for the top roll 21 to apply 'extra pressure loading to the rolls in addition to their weight.

In a conventional calender stack generally of the construction shown in FIG. 1, the arms 25 all have fixed pivots 26 and are dimensioned to hold all of the rolls 2042 with their axes in a common vertical plane with the axis of the king roll 15. All of these rolls above roll 15 are successively driven by engagement with the adjacent lower roll, and the pressure in each nip is successively increased from top to bottom so that maximum nlp pressure is developed between the king and queen rolls 15 and 20.

Under these operating conditions, and with the king roll 15 rotating in clockwise direction as viewed in FIG. 1, the transmission of driving torque from roll 15 to roll 20 develops a force tending to urge roll 20 out of the direct line between roll 15 and the lowermost roll 22, and this force has its maximum effect at' the mid-point of roll 20 which is furthest removed from the restraining action of the associated arms 25. Any bowing of roll 20 which results from this torque force is then immediately accentuated by the pressure loading of the rolls thereabove, which tends to squeeze roll 20 further out of the common vertical plane with the other rolls.

Both of these conditions just described tend to become pressure loading and/ or the speed operation, and also these conditions are accentuated depending upon the width of the calender and resulting length of the rolls. Furthermore, these conditions result both in non-uniform. nip pressure conditions non-uniform calenders, and also in uneven wearing of the rolls. In addition, they are not subject to curing by adjustment of the crown of the king roll 15 in the usual ways, since they tend rather to, counteract the effects of variation in crown.

In accordance with the present invention, it has been determined that the conditions just described can be overcome and the resulting problems eliminated by mounting one or more of the intermediate rolls in laterally offset relation from the fixed plane occupied by the axis of the king roll 15, and particularly by so constructing and effectively reduced to zero. Thus in aplying the invention to the example just described, the queen roll 20 should be so mounted that its axis is offset to the left in FIG. 1

from the plane defined by the axes of roll 15 and the lower-most roll 22, and the amount of this offset should be such that the pressure of the upper rolls tending to squeeze roll 20 further to the left is balanced by the torque forces tending to draw it back and through its nips with roll 15 and the adjacent roll 22. In addition, since these forces vary with changes in pressure, speed and caliper of the sheet, the invention prefreably provides for lateral adjustment of the roll 20 to establish its optimum position for each different set of operating conditions.

Adjustable mountings in accordance with the invention for the queen roll 20 and one of the intermediate rolls 22 are indicated at 40 in FIG. 1 and shown in enlarged detail in FIG. 2. As shown in FIG. 2, each of the arms 25 is in fact a pair of arms straddling the column 11 and supported by a common pivot pin 42 carried by a bracket 44 mounted on column 11. The pivot pin 45 for the arms 25 supporting each adjustable roll, however, has a pair of eccentric portions 46 which are journalled in the arms 25, and means are provided for rotating the pin 45 in backet 44 in order to change the position of the eccentrics 46 and thereby to move the arms 25 and associated roll laterally with respect to the plane defined by the axis of the roll 15 and other fixedly mounted rolls 22.

The adjusting means for pin 45 may take a variety of forms and is shown as comprising a worm gear drive to a gear 50 secured on an extension 51 of the pin 45. The gear train to gear 50 originates from a worm 52 shown as provided with alternate manual and power drives from a handle 54 and electric motor 55. The worm 52 drives a gear 56 on the shaft of a second worm 57 meshing with a gear 58, and the gear 58 is in turn on the shaft of a worm 60 which drives the gear 50 on pin 45. Thus rotation of the driving worm 52 in either direction will result in rotation of pin 45 to move the axis of the associated roll back and forth through the full range provided by the eccentric 46, and tests indicate that satisfactory results are obtained with this range of movement of the order of one inch.

While it is possible and practical under some conditions to adjust each of the adjustably mounted rolls experimentally until desired operating conditions are obtained, the invention provides for sensing or otherwise determining the lateral thrust forces on each of these rolls and for correspondingly effecting its adjustment to the optimum position. Thus FIG. 2 shows a strain gauge 65 of conventional construction incorporated in one of the arms 25 and connected with control circuits in the console 66 which will preferably include a visual dial 67 capable of registering variations in both directions from conditions of zero thrust forces on arm 25. With such an arrangement of strain gauge and control circuits, it is equally practicable sociated roll manually, by means of the handle 54, until the strain gauge registers zero thrust conditions, or the control circuits may be directly connected to actuate the associated motor 55 in the proper direction to establish zero thrust conditions.

For the reasons explained, it appears to be most important in the practice of the invention to provide an adjustable mounting for the queen roll 20, particularly because it is subject to the maximum pressures and torque in operation. The invention contemplates, however, the provision of an adjustable mounting for additional intermediate rolls, including as one example, each even numbered intermediate roll. It is also possible that for some purposes it will be found desirable to apply an adjustable mounting in accordance with the invention to all rolls above the king roll, in which event it is likely that the normal arrangement of the rolls will be with their axes defining an arc of relatively long radius.

FIGS. 3 and 4 illustrate another application of the invention to an open side calender stack, particularly to a stack wherein each of the intermediate rolls 70 is supported at one end of a single arm 25' having its other end for the operator to adjust the asforked to straddle its mounting bracket 72 on the adjacent side of the frame column 11'. FIGS. 3 and 4 show an adjustable mounting in accordance with the invention for the roll 70 in which the pin 75 is similar in design to the pin 45 and has its eccentric portions 76 journaled in the fork end of arm 25 so that when it is rotated in the bracket, the pivot axis of the arm 25' will move laterally. The drive mechanism 40 for rotating the pin 75 is accordingly shown as of essentially the same construction described in connection with FIG. 2, and a strain gauge 65' is indicated diagrammatically in FIGS. 3-4.

FIG. 5 illustrates fragmentarily the application of the invention as applied to one of the intermediate rolls 80 of a calender of the closed side or A-frame type. Each of the lower and upper rolls 80 in FIG. 5 is jour-naled in a bearing 81 mounted in a usual manner for vertical sliding movement as by means of guides 82. The intermediate roll 80 in FIG. 5, however, is adjustably mounted in accordance with the invention as now described.

The bearing 84 for the adjustable roll 80 in FIG. 5 is mounted for lateral adjustment in a carriage 85 mounted similarly to the bearing 81 for vertical movement on guides 82. The bearing 84 is supported for sliding movement in this carriage 85 by means such as gibs 86, and this movement is shown as controlled by a lead screw 88 mounted in the carriage 85 and threaded through a boss 90 on the bearing 84. The screw 88 is shown as provided with a manual handle 91, and a strain gauge is indicated as mounted on the boss 90 for reference in the manner described in connection with FIG. 2. It will be apparent that a motor drive controlled by the strain gauge can be substituted for the handle 91, also as described in connection with "FIG. 2, to establish the proper offset position of the axis of the adjustable roll 80 with respect to the plane defined by the axes of the immediately adjacent rolls 80 under all conditions of pressure loading and speed of the stack.

The principles of the invention as outlined above are not limited to use with calender stacks and are equally applicable to other similar combinations of three or more rolls, such as in breaker stacks and multiple .roll presses. It is accordingly to be understood that references herein to calender stacks are primarily for purposes of illustration, and that while the forms of apparatus herein described constitute preferred embodiments of the invention, the invention is not limited to these precise forms of apparatus, and changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In a multiple roll stack comprising one roll intermediate two other rolls and forming a pressure nip with each thereof, and means for driving one of said rolls to cause rotation of all thereof, the combination of frame means supporting both of said other rolls with their axes in substantially fixed relation defining a plane, adjustable means supporting said intermediate roll for movement generally transversely of said plane, means for determining the thrust forces on said intermediate roll directed generally transversely of said plane deriving from the pressure and torque applied to said intermediate roll under the operating conditions of said stack, and means for operating said adjustable means in accordance with said determining means to effect substantial neutralization of said thrust forces.

2. In a multiple roll stack comprising one roll intermediate two other rolls and forming a pressure nip with each thereof, and means for driving one of said rolls to cause rotation of all thereof the combination of frame means supporting both of said other rolls with their axes in substantially fixed relation defining a plane, a bearing journaling each end of said intermediate roll, means supporting each said bearing on said frame for movement generally parallel with said plane, means for determining the thrust forces on said intermediate roll directed generally transversely of said plane deriving from the pressure and torque applied to said intermediate roll under the operating conditions of said stack, and adjustable means cooperating with each said supporting means to eflect movement of the associated said bearing generally transversely of said plane in accordance with said determining means to eifect substantial neutralization of said thrust forces.

3. The combination defined in claim 2 wherein said determining means includes means for continuously sensing said thrust forces, and comprising means controlled by said sensing means for operating said adjustable means to effect substantial neutralization of said thrust forces.

4. The combination defined in claim 2 comprising an arm connected at one end to each said bearing, means forming a pivotal connection between the other end of each said arm and said frame means, and means for eflect ing lateral adjustment of the axis of said pivotal connections with respect to said frame means.

5. The combination defined in claim 2 comprising carriage means supporting each said bearing for movement parallel with said plane, and means forming a laterally adjustable mounting for each said bearing in the associated said carriage means.

References Cited UNITED STATES PATENTS 1,423,969 7/ 1922 Schurmann 100162 2,455,285 11/ 1948 Versaw. 3,044,392 7/1962 Minarik 100-162 3,066,876 12/ 1962 Verdier 100161 X 3,180,251 4/ 1965 Tidbury 100-163 FOREIGN PATENTS 12,5 8 8 1/ 1881 Germany.

7,992 3/ 1911 Great Britain.

LOUIS O. MAASSEL, Primary Examiner. 

1. IN A MULTIPLE ROLL STACK COMPRISING ONE ROLL INTERMEDIATE TWO OTHER ROLLS AND FORMING A PRESSURE NIP WITH EACH THEREOF, AND MEANS FOR DRIVING ONE OF SAID ROLLS TO CAUSE ROTATION OF ALL THEREOF, THE COMBINATION OF FRAME MEANS SUPPORTING BOTH OF SAID OTHER ROLLS WITH THEIR AXES IN SUBSTANTIALLY FIXED RELATION DEFINING A PLANE, ADJUSTABLE MEANS SUPPORTING SAID INTERMEDIATE ROLL FOR MOVEMENT GENERALLY TRANSVERSELY OF SAID PLANE, MEANS FOR DETERMINING THE THRUST FORCES ON SAID INTERMEDIATE ROLL DIRECTED GENERALLY TRANSVERSELY OF SAID PLANE DERIVING FROM THE PRESSURE AND TORQUE APPLIED TO SAID INTERMEDIATE ROLL UNDER THE OPERATING CONDITIONS OF SAID STACK, AND MEANS FOR OPERATING SAID ADJUSTABLE MEANS IN ACCORDANCE WITH SAID DETERMINING MEANS TO EFFECT SUBSTANTIAL NEUTRALIZATION OF SAID THRUST FORCES. 